Added StatusSimilarityService to check against spamming same statuses over and over

• Added:
- StatusSimilarityService to check against spamming same statuses over and over
- StatusSimilarityService check to PostStatusService and EditStatusService

app/services/edit_status_service.rb

@@ -25,6 +25,7 @@ class EditStatusService < BaseService
 
     return idempotency_duplicate if idempotency_given? && idempotency_duplicate?
 
+    validate_similarity!
     validate_links!
     validate_media!
     preprocess_attributes!
@@ -92,6 +93,10 @@ class EditStatusService < BaseService
     raise GabSocial::ValidationError, I18n.t('media_attachments.validations.images_and_video') if @media.size > 1 && hasVideoOrGif
   end
 
+  def validate_similarity!
+    raise GabSocial::NotPermittedError if StatusSimilarityService.new.call?(@text, @account.id)
+  end
+
   def validate_links!
     raise GabSocial::LinkBlockedError if LinkBlock.block?(@text)
   end

app/services/post_status_service.rb

@@ -34,6 +34,7 @@ class PostStatusService < BaseService
 
     return idempotency_duplicate if idempotency_given? && idempotency_duplicate?
 
+    validate_similarity!
     validate_links!
     validate_media!
     validate_group!
@@ -159,6 +160,10 @@ class PostStatusService < BaseService
     raise GabSocial::ValidationError, I18n.t('media_attachments.validations.images_and_video') if @media.size > 1 && hasVideoOrGif
   end
 
+  def validate_similarity!
+    raise GabSocial::NotPermittedError if StatusSimilarityService.new.call?(@text, @account.id)
+  end
+
   def validate_links!
     raise GabSocial::NotPermittedError if LinkBlock.block?(@text)
   end

app/services/status_similarity_service.rb

@@ -0,0 +1,37 @@
+# frozen_string_literal: true
+
+require 'similar_text'
+
+class StatusSimilarityService < BaseService
+  def call?(status_text = "", account_id = nil)
+    @status_text = status_text
+    @account_id = account_id
+
+    # Not alike if no status_text or no account
+    # : todo : come up with solution for same image spamming
+    return false if @status_text.length == 0 || @account_id.nil?
+
+    alike?
+  end
+
+  private
+
+  def alike?
+    last_status_text = nil
+    key = "last_status_from_account:#{@account_id}"
+
+    Redis.current.with do |conn|
+      last_status_text = conn.get(key) || ""
+      conn.setex(key, 300, @status_text)
+    end
+
+    if last_status_text.nil? || last_status_text.empty? || last_status_text.length == 0
+      return false
+    end
+
+    likeness = last_status_text.similar(@status_text)
+
+    likeness > 85
+  end
+
+end